In recent years, electronic devices have been introduced for controlling various electrical apparatuses in a vehicle such as an automobile. In an electric power steering apparatus, as an example of an electrical apparatus, into which an electronic device is incorporated, a housing in which an electric motor for steering an automobile housed is provided with a motor drive unit and the electronic device is mounted on the motor drive unit. The electronic device is incorporated as a power module into the motor drive unit.
The power module is configured to be a so-called semiconductor module on which a power element such as a Field Effect Transistor (FET) or an Insulated Gate Bipolar Transistor (IGBT) suitable for controlling an electrical apparatus such as an electric power steering apparatus which is driven with a relatively large current. Such a type of power module is also called “in-vehicle module”, because it is mounted on a vehicle.
For example, a technique described in PTL 1 is known as such a type of semiconductor module. In this technique, wiring is used as electrical interconnections connecting wiring patterns and bare-chip transistors on a metal substrate.
For example, as a technique described in PTL 2, lead components electrically connecting semiconductor devices mounted on a metal substrate are formed to be larger than electrodes on a semiconductor, and in addition, to have plural contacts or to have an increased contact width so as to ensure reliability of contact portions.
For example, as a technique described in PTL 3, a stand-up folded portion is formed or a fuse shape (wave shape) is formed in the wiring so as to reduce the stress of connector wiring.